Electric sterilizer



Jan. 15, 1929. 1,699,001

c. F. LAUDERDALE ELECTRIC .STERILIZER Filed Dec. 5, 1926 F12,Shee?'-Sheet 2 24 I do WITNESSES G- ATTORNEY Patented Jan. 15, 1929.

NITED STATES PATENT OFFICE} CHAR-IN F. .LAUDERDALE, OFIZORTLAND, OREGON; F. REED MGBRIZDE ADMINISTRATOR 4 \OF SAID vLAUDERDALE, DECEASED.

'ELEGTRIC STERILIZER.

Application filed December 3, 1926. Serial No. 152,412.

This invention relates to an electric sterilizer, and has been devised with particular reference to its use in heating a medium in which dental or other instruments may be immersed. Ha medium having a comparatively high boiling point is used, it maybe heated in an-open container, and the ster1l1- zat-ion will ib'e eliected much :more quickly than with waterwhich, when unconfined, will boil and evaporate at 212 If heavy oil, like vaseline, is :used :as the medium, it may be heated to a comparatively high temperature without boiling-and a thin film will "remain on the instruments to lubricate the same, while the heat will vaporize and remove any water or aqueous solution which may be on the instrument, and will thereby prevent :the instrnuments tromicorroding.

It is also an object of the invention to provide a sterilizeroffthisitypezhaving a thermo- Jst-at for automatically maintaining the temperature between :certain limits, and also to provide :certain "devices to prevent arcing as the circuit through 'the heating :element is made and broken.

The specific construction of :the invention and theradvantages thereof will the more'particularly "describe-din connection with the accompany'ing drawings, which illustrate :t-he same in v:its preferred form.

.In the drawings Figure lxis a perspective view ofthe/inven- Figure 2 is a verticalsectional view thereof. Figure 3 isaplan view ofthe bowl with'the thermostatically controlled switch in closed position.

Figure 4 is asimilar vie-w with :the switch open,

Figure 5 is a diagram showingone way in which the wiring may be arranged.

Figure -6 is a diagram showing :another way in which the wiring may be arranged.

Figure? shows -.a modified arrangement for thermostatically controlling the switch.

The sterilizer, in its present form, is mounted in a bell-shaped housing 10, having at its lower edge a reinforcing flanged rim 11 which is secured by screws 12 or the like to a suitable base 13 of non-conductive material. At the upper end of the housing 10, a bowl 14 is mounted, and is formed with a nwith the blade 27 extenddownwardly through the plug 19.

-In the arrangement shown in Figures 1, '2sand-5, the wire 21 is connected to one side of the line which supplies the-current, while the -wire.22 is electrically connected through a conductor 23 to a switch blade 24, secured ina holder:25, which is mounted on the side of the housing 10. The extremity of the switch blade 24 is adapted to be connected through contact points 26 to a stationary blade-27, also secured in the holder 25. The blade 27 :isco'nnected by a conductor 28 to a. wire 29, which'leads to the other side of the line.

Thecontact between the switch blade 24 andthe stationary blade 27 is controlled by a thermostatBO, which is secured to the bowl 14, and extends about the outer face of the blade 24 in contact therewith. The blade 24 is resilient, 'and, as shown in Figures 1 to 4, is tensioned so as to spring out of contact except when the contact is closed by the action of the thermostat S0. The thermostat is adapted, at ordinary temperatures, to engage the switch blade 24 and hold the contactclosed, but is so adjusted that it willexpand sufiiciently at a predetermined temperature to release the switch blade, and permit the circuit through the same to be broken.

Int-he modification shown in Figure 7, the .free end of the thermostat is adjacent the bowl, as shown at 32, while the spring blade 24 'is tensioned so as to remain normally closed. The thermostat, when a mined temperature has been reached, expands and acts on the spring blade 24 to open the switch, and when the temperature again :talls so that the thermostat contracts, the tension of the blade 24 causes the latter to close predeter- I again. In either form of switch controlling device, theend of the spring blade may be provided with an adjustable screw an, so as to regulate the temperature at which the switch opens.

When the sterilizer is in use, the circuit through the contact points 26 will be made and broken frequently in response to variations in temperature, and I have, therefore, provided suitable means to prevent destructive arcing at these points. A suitable condenser 31 is mounted within the housing 10, and is electrically connected to the conductors 2S and 28 on opposite sides of the switch. An incandescent lamp 32 is mounted in a socket 38 secured to the base 13, andis connected in the circuit in parallel relation to the condenser and the switch.

Instead of the wiring shown in Figure 5, the heating element 20'rnay be connected as shown in Figure 6, one end being connected to the wire 21, and the other end being connected by .a wire 22 directly to the switch blade 24-, so that the heating element is electrically parallel to the light 32. i

The wires 21 and 29m'ay be carried up through the base 13 in a suitable extension cord 84, which may be connected to an electric socket in theusual manner.

In the operation of the sterilizer, Vaseline or a similar compound is placed within the bowl 1%, and will be raisedto a predetermined temperature, which is automatically controlled by means of the thermostat 30 and switch blade 3%. As the temperature reaches the desired point, the circuit through the contact points 26 is automatically interrupted, but there is no arcing at these points, owing to the parallel circuit through the lamp 32 and the condenser 81. The temperature at-which the circuit through the contact points 26 will be interrupted is preferably higher than t boiling point of water, so that the sterilization may be quickly effected, and the use of oil as a conducting medium for the heat not only allows a higher temperature than water unconfined, but also leaves a thin non-aqueous film on. the instrument thus sterilized. This thin film of oil not only prevents corrosion, but, in the case of dental instruments and other appliances having gears, joints or movable parts, provides lubrication for the same. p 7

While I have described in detail the preferred form of the invention and the method of using the same, it is obvious that the same may be considerably modified without any material departure from the salient features f the invention as claimed.

What is claimed is:

1. In an electric sterilizer, the combination of a bowl having an electric heating element within the wall thereof, an electric circuit connected with said heating element, a switch in said circuit, thermostatic means for controlling said switch to maintain the temperature of the bowl between certain predetermined limits, a condenser, and an incandes cent lamparranged electrically parallel to said switch blade to prevent arcing when the circuit through the switch blade is made and broken. 7

2. In an electric sterilizer, the combination of base, a housing secured thereon, an open bowl supported by the housing and adapted to contain a substance in which instruments may be immersed, an electric heating elementwithin thewall of the bowl, an electric circuit connected with said heating element, a spring switch blade in said circuit, a thermostat cooperating with the spring switch blade to keep the latter closed when at ordinary temperature and to open when a predetermined temperature is attained, a condenser within the housing, and an incandescent lamp mounted in the base and arranged electricall 7 parallel to the switch blade to prevent arcing when the circuit through the switch blade is made and broken.

3. In an electric sterilizer, the combination of a base, a housing secured thereon, an open bowl supported by the housing and adapted to contain a substance in which the instruments may be immersed, an electric heating element within the wall of the bowl, an electric circuit connected with said heating element, a spring switch blade in said circuit supported near said bowl, a thermostat secured to and extending around said bowl adjacent the extremity of the blade, said thermostat cooperating with the spring blade to cause the latter to remain closed when at ordinary temperature and to cause the same to open when a predetermined; temperature has been. attained, a condenser within the housing, and an incandescent lamp mounted within the base and arranged electrically parallel to said switch blade to prevent arcing when the circuit through the switch blade is made and broken.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature.

cnarm r. LAUDERDALE. 

